Question

a geologist finds some tilted sedimentary rock layers. which conclusion can the geologist draw by looking at the rock layers? their absolute age is 600 million years. they were tilted before they were deposited. they were originally deposited horizontally. the youngest layer was originally deposited as the bottom layer.

Explanation:

• For the option "Their absolute age is 600 million years": Tilted sedimentary rock layers alone don't provide absolute age; absolute dating methods (like radiometric dating) are needed, so this is incorrect.
• For the option "They were tilted before they were deposited": Sedimentary rocks are deposited in horizontal layers first (principle of original horizontality), so tilting happens after deposition, making this wrong.
• For the option "They were originally deposited horizontally": The principle of original horizontality states that sedimentary rocks are initially deposited in horizontal layers. Tilted layers imply they were tilted after deposition, so they were originally horizontal. This is correct.
• For the option "The youngest layer was originally deposited as the bottom layer": By the principle of superposition, the youngest layer is on top, and the oldest is at the bottom in undisturbed sedimentary layers. So this is incorrect.

Answer:

C. They were originally deposited horizontally (assuming the options are labeled A, B, C, D with C being "They were originally deposited horizontally")